This study, which is a competing renewal application, has three aims: In Aim 1, we expand our current ongoing study of longitudinal use of eye care services among the elderly for diabetic retinopathy (DR), glaucoma, and age-related macular degeneration (ARMD) to include cataract. Arm 1 will describe trends in use of therapeutic interventions for the four eye diseases; assess determinants of use of therapeutic procedures for glaucoma, DR, and ARMD, as well as the role of Medicare pricing policies in determining rates of cataract surgery. Aim 2 will extend our analysis of adherence with practice guidelines for vision care and its effects on visual outcomes to include use of therapeutic services, and their productivity as a function of regular monitoring. We add additional outcome measures not used in our current study, pharmaceutical as well as other therapies, longer time periods for analysis, and new data. In Aim 3, we assess utilization, adherence to guidelines, the productivity of various therapeutic interventions, and outcomes associated with diabetes mellitus (DM) other than retinopathy (e.g., heart attack, stroke, and amputation) for elderly persons with diabetes mellitus. An econometric framework for assessing joint effects of regular monitoring and treatment will be further developed and implemented. Data for this four-year extension will come from the National Long-Term Care Surveys merged with Medicare claims and enrollment data for 1984-2005, the Medicare 5% sample, and on persons aged 65+ from the Aging Dynamics of the Oldest-Old (AHEAD) and Health and Retirement Surveys (HRS) merged with Medicare claims, and the Current Medicare Beneficiary Survey (MCBS) merged with Medicare claims. Ten papers are anticipated for this four-year study. [unreadable] [unreadable]